Developing an Analytical Toxicology Service

Effectiveness of a Reliable Toxicological Analysis for a Correct Diagnosis of Acute Intoxication in Pediatrics: 2-Year Experience of an Analytical Toxicological Laboratory

OBJECTIVES

This study aimed to assess the role of the laboratory of toxicology as a support for a correct diagnosis of intoxication through the application of a reliable analytical approach, critically designed to meet pediatric needs.

METHODS

Data collected from 360 cases of suspected intoxications in pediatric patients (aged 1 day to 17 years) during the period 2018 to 2019 are presented. Toxicological analyses were performed through different techniques (immunoassay and chromatography) with parameters (limit of detection and cut-off) adjusted according to pediatric needs to produce reliable toxicological data for a wide number of prescription drugs, drugs of abuse, and poisons.

RESULTS

We present results about (1) agents involved in suspected poisonings and the methods adopted for a definite analytical diagnosis, (2) the assessment of the concordance of results for analyses proceeded by different techniques, and (3) the percentage of agreement between analytical result and clinical suspicion.

CONCLUSIONS

An analytical approach critically designed to minimize misinterpretation of laboratory data and able to provide reliable results for a wide number of substances in a time compatible with the urgency represents a useful support for a correct diagnosis of intoxication in pediatrics.

How can analytical diagnostics in clinical toxicology be successfully performed today?

This article discusses current strategies for efficient analytical diagnostics in clinical toxicology. The tasks for such diagnostics, different analytical strategies and various methods were reviewed. They cover mainly gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry procedures for target or comprehensive screening for drugs (of abuse) and poisons, and for quantification in blood. Quality control aspects and strategies for competent interpretation of the analytical result in correlation with the clinical signs presented by the patient are discussed.

Collection of biological samples in forensic toxicology

Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.

Clinical findings and cholinesterase levels in children of organophosphates and carbamates poisoning

INTRODUCTION

Exposure to organophosphate and carbamate insecticides inhibits cholinesterase activity and interferes with synaptic transmission both centrally and peripherally at muscarinic receptors and nicotinic receptors. The study reported the usefulness of plasma cholinesterase ChE activity assays for diagnosis and the management of organophosphate and carbamate toxicity in children.

METHODS

A retrospective study was conducted on children with organophosphate and carbamate poisoning. Forty-seven patients were included. The diagnosis was confirmed by measuring plasma cholinesterase levels. Atropine was given intravenous (0.02 mg/kg) and repeated until secretions were controlled. Obidoxime chloride was administered as 4-8 mg/kg/dose for children with organophosphate poisoning and to those in whom the ingested material was unidentified on admission.

DISCUSSION

Most of the patients showed marked reactivation in plasma ChE within several hours and recovered completely within 24 h of admission. Complications were observed in 17 patients (36%). Mechanical ventilatory support was required in six patients. The duration intensive care stay was 3 +/- 2.4 days.

CONCLUSION

Low plasma ChE levels support the diagnosis of insecticides poisoning, but no significant association is present between the severity of poisoning and plasma ChE levels. Atropine should be used as soon as possible to counteract the muscarinic effects. Appropriate management and early recognition of the complications may decrease the mortality rate.

Reporting units for therapeutic drug monitoring: a correctable source of potential clinical error

Variation between laboratories and reference sources in the units used for reporting pathology results raises the possibility of medical error. Data submitted to the RCPA Quality Assurance Programs demonstrate wide variation in the units used for reporting therapeutic drug concentrations. This potential source of medical error needs to be addressed by all parties involved in communicating drug concentrations and providing support information.

Demands on scientific studies in clinical toxicology

Scientific case studies in clinical toxicology on single cases or series of similar cases should document sufficient information on the clinical methodology and observations, the medical laboratory methodology and results, the toxicological analyses methodology and results, the source of used reference values for drug/poison concentrations and kinetics with critical discussion of such values, a description and discussion of the toxicodynamic, the toxicological and the kinetic properties of the detected drugs and/or poisons. The data management, statistical analysis and finally the clinical and/or analytical outcomes must also be described and discussed in correlation to already published data. Statistical methods used for evaluation of clinical as well as for analytical data should be described in detail. When possible, quantitative findings should be presented with appropriate indicators of measurement error or uncertainty. Requirements for such studies are discussed.